What is demodex and how is it treated?
Humans can be suitable hosts for many microscopic organisms, and one example of these unsuspected guests on human skin is a parasite called Demodex mites. Almost no adult human exists without Demodex mites living on their skin, but when the population density of these parasites increases, many skin and hair problems intensify.
History of Demodex:
Scientists have known about Demodex parasites for over a century, but until a few years ago, they didn't pay much attention to it, so this parasite was not introduced to the general public. Researchers have found that humans have been hosts to these organisms since ancient times, dating back to about 20,000 years ago, although nowadays, due to the increase in urban population and public places, especially centers that are effective in transmitting parasites, such as beauty salons, gyms, swimming pools, etc., its prevalence has increased.
Lifecycle and Lifespan of Demodex:
The life cycle of these mites consists of 5 stages. Demodex mites mate on the surface of human skin at night and lay eggs inside hair follicles or sebaceous glands after about 12 hours. Each egg-laying stage contains about 50 to 60 eggs that reside in hair follicles and sebaceous glands. Eggs develop into larvae and six-legged nymphs after a few days, which mature after a week to enter the reproductive cycle. Their period from maturation to adulthood is about a week, and the lifespan of a Demodex mite is approximately 30 to 90 days. These organisms retain all the waste materials produced in their bodies throughout their lives until they die.
Demodex parasites are microscopic organisms that live in human hair follicles and sebaceous glands. Demodex feeds easily on skin oils and cosmetic and hygiene products.
Morphological Characteristics and Classification:
These parasites cannot be seen with the naked eye, but their invisibility does not mean they don't exist. These microscopic mites are arachnid-like creatures with eight small, hairy legs near their heads, and their bodies are semi-transparent. However, they closely resemble worms and can be found on the skin of every adult human. These insects spend their entire lives on human skin, where they are born, reproduce, and die after about one to three months.
Two species of these microscopic creatures reside on human skin, especially in the area of the head and face: Demodex folliculorum and Demodex brevis. These creatures are classified within the arachnid group, with their closest relatives being among spiders and mites.
These parasites inhabit various areas of human skin. Demodex folliculorum typically resides within the hair follicles of the scalp and face, while Demodex brevis lives inside the sebaceous glands of the skin. The reason for the abundance of these creatures on the human scalp and face is the higher presence of follicles and sebaceous glands compared to other parts of the body.
To date, about sixty-five species of Demodex mites have been identified, but only two species live on human skin, both commonly referred to as "hair follicle mites" or simply "face mites." Demodex folliculorum, known as the follicle mite in humans, and Demodex brevis, known as the sebaceous gland mite. These parasites are found in hair follicles and sebaceous glands, especially in eyelashes, nose, cheeks, areas around the nose, and around the ears, and they feed on subcutaneous secretions, especially sebum.
These parasites are very small, measuring between 0.3 to 0.4 millimeters, and have a cigar-like shape. There is a particular difference in the distribution of the two species on the skin. Demodex folliculorum is found in high and noticeable densities, while Demodex brevis inhabits a wider area of the human body. The ratio of Demodex brevis to Demodex folliculorum is different among men (1:4) and women (1:10).
Another type is Demodex canis, whose natural host is domestic dogs. Although these parasites can temporarily infest humans, they cannot survive on human skin for long and therefore die after a short period, not considered a common parasite of humans and animals.
Symptoms of Demodex Infestation:
These parasites retain all the waste materials produced in their bodies throughout their lives until they die, which can exacerbate:
- Skin infections
- Acne
- Rosacea
- Pimples
- Itching
- Hair loss
- Thinning and weakening of hair
- Skin itching
- Skin wrinkles
- Premature skin aging
- Dry and rough skin
- Blackheads
- Change in facial skin color
- Freckles and moles
- Atopic dermatitis
- Dermatitis
- Change in skin color on the face
- And other skin and hair problems
Additionally, these parasites can contribute to the exacerbation of other skin and hair problems. For example, scientific and experimental studies show that the population of Demodex mites in the faces of individuals with rosacea is much higher than in the faces of those without this problem. The average density of Demodex mites on the skin of rosacea patients is 8.10 mites, compared to 0.7 mites per square centimeter in healthy individuals. Research has shown that Demodex mites transmit bacteria to the skin around the face.
